Gyro vertical



July 22, 1941. .1F.'ARTER 2,249,744

GYRO VERTI CAL Filed March 5, 1938 5 Sheets-Sheet l 1 5 I I Egu TIHTER July 22, 1941. L.. F. CARTER yGYRO VERTICAL Filed March 5, 195B 3 Sheets-Sheet 2 il L July 22, 1941.` F, CARTER 2,249,744

GYRO VERTI CAL INVENTOR Yue wie l l ORNEY riod during which it is most important that the Patented lJuly 22, 1941 UNITED" sTATEs PATENT OFFICE Grao VERTICAL Leslie F. Carter, Leonia, N. I., assignor to Sperry Gyroscope Company, Inc., corporation o! New York Brooklyn, N. Y.. a

Application March 5, 1938, Serial N0. 194,039

4 Claims.

This invention relates to the art of gyroscopic artiilcial horizons or gyro verticals, wherein the purpose is to maintain a truly horizontal planeV or reference vertical regardless of accelerationforces due to turning and changes of speed of the vehicle on which the instrument is mounted.

pendulous blades which differentially cover airports in the bottom 'of .the casing, the present practice being to balance the gyroscope about its trunnion supports with the auxiliary pendulums hanging free. Under the action of lateral acceleration forces, the auxiliary pendulums swing in the direction of the applied force and thus open a port and cause the gyro to slowly precess from the vertical in following the inclination of the control pendulums. If the force is strong, the pendulum will swing over until it strikes a stop, which results, in effect, in slightly lowering the center of gravity of the system since at that time the/center of gravity of the auxiliary pendulum ceases to act at the pivotal point of support and is lowered to its true center of gravity.

According to the present invention, I propose to remedy both of these defects. First, I propose to cut off the erecting force during turns so that the gyro will not be disturbed at that time.

When cutting ofi the erection force, however, I propose to leave the spinning torque on the gyro unaffected, vsince during long turns, if the spinning jets are interfered with, serious loss of speed of the rotor may result. To this endI propose to provide two independent air supplies, one for; spinning the rotor and the other for' the erecting'- torque. I also propose to so mount and balance the auxiliary pendulums that at the time the' vacceleration forcev is acting, the` gyro will be in true equilibrium, since this is the pcgyro should be in equilibrium.

One method of accomplishing this is by bal- .ancing the gyroscope about its gimbal support 'l with. the pendulums locked to the gyro or, in"

other words, under the same 4conditions that 55 (Cl. I4-5) would arise during the action of an acceleration force. While this results in'making the gyro' slightly anti-pendulous, thatis, top-heavy when the auxiliary pendulums are hanging free, this 5 has no detrimental effect since the erection forces are well able tomaintain the gyro erect regardless of this slight unbalance.

Another method of accomplishing thisis to pivot the auxiliary pendulum or pendulums in the same horizontal plane as the trunnion axis of the gyro, since whatever torque is exerted by d the pendulum when displaced by the action of acceleration forces is rendered ineiiective by the fact that it has no lever arm.

forms my invention may assume,

^ Fig. 1 is a side elevation, partly in section, of the form of gyro vertical four auxiliary pendulums as the gravitational controller.

Fig. 2 is a vertical section through the gyroscope casing and rotor, taken at right angles to Fig. 1.

Fig. 3 is a horizontal section taken through the gimbal ring pivots.

Fig. 4 is a diagrammatic view'showing how the erecting device may be cut oil automatically from a turn indicator.

Fig. 5 is a horizontal section taken substantial- I ly on line 5-5 of Fig. 2, with the pendulums omitted.

Fig. 6 is a vertical section of a gyroscope, showing a modified form of the invention.

Fig. 'I is a horizontal section taken on line l-l lof Fig. 6, looking in the direction of the arrows.

Fig. 8 is a sectional detail showing a still fure ther modification.

Fig. 9 is a bottom. view of the bottom portion of the parts shown in Fig. 8.

The gyroscope is shown as enclosed within a rotor bearing casing l which is universally gimbaled by being trunnioned in horizontal trunnions, 2, 2 in a gim-bal ring 3 which, in turn, is trunnioned in horizontal trunnions 4, I', normal to trunnions 2, 2', in the outer supporting frame 3. The channel Il, in turn, communicates with- -passages I2 through trunnion 4 and thence leads Referring to the drawings, showing several without the casing through channels I3. The instrument is shown as of the vacuum driven type, air being continuously exhausted from the casing through pipe I4 and a portion of the air enters through a screen I 5 and through channels I3,

Instead of allowing the air used to spin the rotor to pass downwardly into the extension 32 to erect the gyroscope, I discharge this air upwardly through holes I6 in the casing. In order to prevent any torq'ues being exerted by the discharge air, I preferably pass this air through baille material, such as loose cotton I'I, and discharge it through a. plurality of apertures I8 and I9 directed upwardly,` and possibly laterally, in symmetrical fashion. i

For supplying the erecting device with air, I provide a separate intake screen 20 which is provided with a shut-oli device 2|. 'I'his may be in the shape of a pair of superimposed discs 2I and 22, each provided with a plurality of apertures 23 and 24.

when the disc 2I is turned in the position shown in Figs. 1 and 4, the intake air is shut 01T. 'I'he disc may be conveniently turned from a knob 25 which may be adjusted by hand during turns or change of speed, or it may be operated automatically from a turn detecting device such as a gyroscopic turn indicator 26 (Fig. 4), which is shown as connected by a link 21 to a pin 28 on knob 25 in Fig. 4, so that precession of the gyro in either direction will close the intake ports 23-24.

It should be noted that the shut-off valve thus provided is mounted in a iixed part secured to casing or frame 5, and not on the sensitive gy-roscope cr gimbal ring, so that the valve may be readily turned on and oii by hand through knob 25, or automatically, without disturbing the gyroscope. Said valve is thereforelocated at the entrance to theY several channels leading through the gimbal ring supporting the hollow gimbal and the rotor bearing casing supported in the gimbal.

'Ihe air, after passing through the screen, enters the gimbal ring 3 through the hollow trunnion 4'. .Thence it passes around the gimbal through a channel 29 and through hollow trunnion 2' and into a channel 30 in the rotor bearing casing. Ihence it passes downwardly through channel 3i and into the hollow extension 32 on the bottom of the casing. Said extension may be provided with the usual two pairs of opposed ports 33 and 34, adjacent to which are mounted the gravitational members in the form of small pendulums 35 and 36 pivoted on shafts 31 and 38 above the ports. The balance and hang of each pendulum may be independently adjustedby small eccentric masses 39 adjustably secured thereto by set screws 40, the position being slightly shifted to change the hang and balance of each pendulum. In the normal position, the pendulums preferably just close all four ports so as to use a minimum amount of air. Upon tilt of the gyro in a counter-clockwise direction in the plane of Fig. 1, for instance, the port 34 would be uncovered slightly, leaving the opposite port covered, and 'thus exerting a torque on the gyro at right angles to the tilt.

When the knob 25 is turned by hand, the adjustment may not only be changed during turns, but at any time it is desired to chang the rate of erection, since obviously by varying t e amount of opening of the ports 24, the rate of flow of the When said apertures are in line, Q air may flow freely in through the screen 20, but

air through the erecting ports may be varied at will. Even when the knob is being adjusted by rigid part `of the casing as soon as the stop is engaged. Ihis has the advantage that 'the affected pendulums strike a stop and thus lower the center of gravity practically at the start of a turn, to thus cause the gyro to become neutrally balanced at that time. Under the conditions assumed, the other pair ofpendulums, the pivotal axis of which is in line with the acceleration force, cannot swing and therefore act as a rigid part of the case. In general, therefore, it may be stated that one pair of pendulums always has to be considered as a pendulous mass because it cannot swing if the gyro tilts'in the plane of their pivotal axis, and the other pair also becomes a pendulous mass as soon as the stop ls reached, which occurs under all ordinary lateral acceleration forces.

Therefore, in the balancing operation pursued in manufacturing the gyroscope, the gyro is preferably balanced with the pendulums locked to the casing, for instance, by means of a rubber band, so that the gyro will be balanced under the action of lateral acceleration forces. Although this results in making the gyro very slightly top-heavy when all pendulums are hanging normally, the erection force is sufiicient to counteract any disturbing eiIect from this condition. 'Ifhe balancing operation is assisted by means of a mass 42 threaded on a rotatable stem 43 Within the hollow extension 32l the stem being rotated by means such as a screw driver inserted in slot 43 so as to adjust the height of the mass.

It is obvious that, if desired, the ports 23 and 24 need not be entirely closed during the turn, but may be left slightly open so as to retain enough erecting force .to counteract any unbalance of the gyro.

While the same general principles of operation are retained in the form of the invention shown in Figs. 6 and 7, a change is made in the type and method of mounting of the gravitational controller.

Where similar, the parts are similarly numbered to Figs. 1, 2 and 3, so that a detailed description of this ligure is omitted.

In this case, the gravitationalgontroller is in the form of a single pendulum 45 which is universally mounted by universal pivot 46 in the same horizontal plane as the main trunnions 2, 2', 4, 4' of the gyro and in the vertical center line of the gyroscope. Bythis means a minimum of disturbing action is exerted on the gyro when the pendulum is displaced, mainly because the pendulum 45 is universally mounted so that it can swing in any plane and therefore does not act as'a. fixed mass on the gyroscope, no matter in which direction the lateral acceleration force acts and, in addition, because the lateral forces thereon have no lever arm about any axis. AIn this form, close stops are unnecessary and in fact are not desirable, the pendulum being permitted to swing within the limits of the enclosing casing,

The erecting air escapes downwardly through one of vertical channels 41, 41', 48, 4 8 and passes laterally through the connected channel 49 in the bottom plate so as to emerge through ports 56, 56' at right angles to the plane of the relative tilt of the pendulum and gyroscope.`

In this form, instead of shutting off the intake air to the erecting ports, the erecting ports are closed or spoiled. According to one modication, a sleeve 50 is slidably mounted on an extension 5I from the bottom of the gyro case, said sleeve being united with a iiexible or expansible container 53, such as a Sylphon, the interior of which is connected through ports 54 with the interior 55 of the bottom of the gyro casing. The Sylphon is therefore exposed to the pressure of the air within'the casing. The pressure is normally insufficient to force the Sylphon downwardly far enough to shut oi the ports 56, but when the pressure rises beyond the Anormal pressure, the Sylphon is forced clownwardly, causing the sleeve 50 to close the ports 56. In the preferred form sleeve 50 is cut away on two sides so that only the ports 56 which lie athwartships are cut off during turns, the others 56 being unaiected, since their pendulums are not affected at this time. (Arrow A in Fig. '1 indicates the airplanes fore and aft line.)

In this form of the invention, means are provided to greatly increase the relative air pressure supplied through'the channel 3| 4to the chamber 55 (as compared to the pressure in the casing 5) during turns to cause the Sylphon to operate. Since independent channels are provided for leading air to the rotor and to the erection fde Vice, it is easy, if necessary, to effect this purpose without changing the rotor speed. However, an increase in the rotor speed during turns is not harmful and therefore I have merely shown a means for varying the negative pressure supplied by the pump to increase the relative air pressure within the chamber 55 during turns. Instead of having the sleeve cut off the ports 56, it may simply spoil the air discharge there-A from as shown in Figs. 8 and 9, illustrating a still further modification. In Fig. 8 the Sylphon 53 is shown in the expanded position, the sleeve 50' having an outwardly bent portion 52 at the bottom thereof having a downwardly: turned rim 51. 'Preferably said rim is cut awry or bent inwardly opposite ports 56' so as not to interfere with the discharge of air from the ports 56',- as in Fig. '7. 'Ihe discharge of air from ports 56, however, strikes the rim 51 and is hence defiected downwardly so that most, if not all, of the lateral reactionl thereof is destroyed, thereby cutting out the erecting force around the transverse axis during turns.

In the form of the invention shown in Figs. 6 to 9, the turn indicating gyro 26, instead of being connected to the shutter at the intake, would be connected to a throttle valve V between the pipe I4' and the vacuum pump. Said valve could be normally partially closed but, when turning, would be opened Wide by hand or by means of a turn indicator gyroscope, so that the vacuum would be increased at that time. This would of the Sylphon 53. Obviously, this could also be applied to a pressure system, in which case a throttle valve at the pump would be operated as before, by a turn indicator or by hand, to give a maximum pressure when turning. In either case, it should be noted, not only is the discharge of air from the ports 56 (Figs. 6, 7 and 8) either stopped or rendered ineffective, but also the discharge of air through the other ports 56' is actually increased during a turn. Since the latter are not affected by acceleration' forces of the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. Having described my invention, what I claim and desire to secure by Letters Patent is:

1. In a gyro vertical, a universally suspended gyroscope mounted in substantially neutral equilibrium, and a plurality of small pendulums pivoted thereon to control, by the relative inclination of thesame and the gyroscope, a source of power to causeerection, each pendulum having a mass eccentrically pivoted thereon and means whereby said mass may be locked in the desired position. Y

2. In an air erected gyro vertical, a universally mounted rotor bearing casing, aplurality of differently facing ports therein for discharging air from the casing, a pendulum pivoted on said casing above each port, a lmass eccentrically pivoted thereon, and means whereby said mass may be locked in the desired position.

decrease the pressure in the outside casing 5 3. In an air spun, air erected gyroscope, a rotor and rotor bearing casing, an air actuated erection device on said casing, a gnnbal ring in which said casing is pivotally mounted, a supporting frame in which said ring is pivotally 'mounted, channel lmeans for leading air in through the pivotal mountings of both said ring and casing and through said ring to within said casing to spin the rotor, separate channel means for leading in air through' both said pivotal mountings and ring to within said casing for actuating said erection device, separate discharge ports for each air supply, and baille means at the discharge ports from the rotor for preventing disturbing torques from the discharged air.

4. In an air spun, air erected gyroscope, a ro-A 'for each air supply, a valve in the erection channel means before said channel enters said gimbal` mounting, and manual means-for adjusting said valve to cut out or lessen the erecting force at will.

' LESLIE F. CARTER. 

